Frame rate preferences in low bit rate video

A double stimulus subjective evaluation was performed to determine preferred frame rates at a fixed bit rate for low bit rate video. Stimuli consisted of eight reference color video sequences of size 352×240 pixels. These were compressed at rates of 100, 200 and 300 kbps for low, medium, and high motion sequences, respectively, using three encoders and frame rates of 10, 15 and 30 frames per second. Twenty-two viewers ranked their frame rate preferences using an adjectival categorical scale. Their preferences were analyzed across sequence content, motion type, and encoder. Viewers preferred a frame rate of 15 frames per second across all categories, with several notable content-based exceptions.